Walnut tree named ‘Ivanhoe’

ABSTRACT

A new and distinct variety of walnut tree denominated ‘Ivanhoe’ is described. This new variety, ‘Ivanhoe’, comes into bearing young, with an excellent yield. ‘Ivanhoe’ forms large-sized walnuts that possess light-colored kernels with little size variation in a given harvest. ‘Ivanhoe’ bears fruit terminally and laterally and yields a crop that can be harvested approximately 4 weeks before ‘Chandler’ (U.S. Plant Pat. No. 4,388). ‘Ivanhoe’ is also protogynous, bearing female flowers before male flowers.

Latin name: Botanical/commercial classification: (Juglans regia)/newEnglish walnut tree cultivar.

Varietal denomination: The varietal denomination of the claimed walnutis ‘Ivanhoe’.

BACKGROUND OF INVENTION

The present invention relates to a new and distinct cultivar of walnuttree (Juglans regia) that has been denominated as ‘Ivanhoe’ and moreparticularly to a walnut tree that has a harvest date approximately 4weeks earlier than the walnut tree cultivar ‘Chandler’ (U.S. Plant Pat.No. 4,388), and that further produces a walnut that is large in sizewith very light colored kernels.

It has long been recognized as desirable to provide walnut trees bearinglarge crops that are ripe for commercial harvesting and shipment earlyin the harvest season. The tree of the present cultivar, ‘Ivanhoe’produces a nut that has a quality similar to the highest qualitycultivar ‘Chandler’ (U.S. Plant Pat. No. 4,388), however the newcultivar is ready for harvest approximately 4 weeks before ‘Chandler,’about the same time as the reference cultivar ‘Payne’ (old cultivar; notpatented).

The new Juglans regia walnut tree of the present invention was createdat Davis, Calif. in 1995 by a controlled pollination between thecultivar ‘Chico’ and ‘UC67-13’ (neither patented). The pedigree isillustrated (FIG. 1).

Seeds from the cross were planted and the resulting 27 trees werecarefully observed along with other trees in the walnut breedingprogram. When they began to bear nuts, data were collected annually onleafing date; first, peak, and last female flower bloom; first, peak;and last male bloom; blight severity; and yield (Table 1). Nuts weresampled and cracked, and data were collected on shell appearance, shellthickness, shell integrity, shell strength, nut weight, kernel weight,percent kernel, ease of kernel removal, kernel color, and percent kernelshrivel (Table 1). A single tree was selected from among progeny of thiscontrolled cross based on its superior attributes. This selection wasoriginally designated ‘UC95-11-14’ and is now designated as the‘Ivanhoe’ cultivar, after the town in California where it performed in asuperior manner. Compared to ‘Ivanhoe’, the parent ‘UC67-13’ isprotandrous, has larger nuts, a slightly later harvesting date, and issusceptible to pistillate flower abscission; the parent ‘Chico’ hassmaller nuts than ‘Ivanhoe’ with a more difficult to extract kernel.

The new ‘Ivanhoe’ cultivar of the present invention has been asexuallyreproduced by grafting at Davis, Calif. on ‘Paradox’ rootstock. Thedistinctive characteristics of the new cultivar have been found to bestable and are transmitted to the new trees when asexually propagated.

SUMMARY OF THE INVENTION

It was found that the walnut cultivar ‘Ivanhoe’ of the present inventionexhibits the following combination of characteristics:

-   -   a) comes into bearing young, with an excellent yield;    -   b) forms large-sized walnuts that possess light-colored kernels        with little size variation in a given harvest;    -   c) bears fruit terminally and laterally;    -   d) yields a crop that can be harvested approximately 4 weeks        before ‘Chandler’ (U.S. Plant Pat. No. 4,388); and    -   e) is protogynous, bearing female flowers before male flowers.

BRIEF DESCRIPTION OF THE TABLE

Table 1 shows tree and nut evaluations for both parents and the mostcommon walnut cultivar ‘Chandler’.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows pedigree of the ‘Ivanhoe’ walnut.

FIG. 2 shows a tree of ‘Ivanhoe’ walnut at 7 years.

FIG. 3 shows bark of ‘Ivanhoe’ walnut.

FIG. 4 shows adaxial view of leaf of ‘Ivanhoe’ walnut.

FIG. 5 shows abaxial view of leaf of ‘Ivanhoe’ walnut.

FIG. 6 shows female flowers of ‘Ivanhoe’ walnut.

FIG. 7 shows catkins (male flowers) of ‘Ivanhoe’ walnut.

FIG. 8 shows hulls of ‘Ivanhoe’ walnut.

FIG. 9 shows nut and kernel of ‘Ivanhoe’ walnut.

BOTANICAL DESCRIPTION OF THE PLANT

The description is based on an ungrafted walnut tree on its own rootsand trees subsequently grafted on ‘Paradox’ rootstock growing in anorchard in Davis, Calif., in selection blocks in Chico, Calif., andParlier, Calif.; as well as in grower trials near Yuba City, Calif.,near Madison, Calif., and near Ivanhoe, Calif. The first data werecollected on the own rooted tree from 1999 at age 3 years, to 2005, age9. Data from 2004 to 2008 were collected from grafted trees.

The Munsell Book of Color is used in the identification of color. Also,common color terms are to be accorded their ordinary dictionarysignificance.

-   Botanical classification: Juglans regia.    -   -   Female parent.—‘UC67-13’.        -   Male parent.—‘Chico’. The pedigree is shown (FIG. 1).-   Plant: The growth habit of the plant is illustrated in FIG. 2. This    7 year old tree is approximately 5.2 m in height with a canopy    diameter of 6.4 meters. The trunk diameter at 1.2 meters above the    ground is approximately 10 cm. The silvery grey bark is typical of    Juglans regia. The young bark is brown (2.9GY 2.3/3.6) and the older    bark is grey (5Y 7.5/2) with raised lighter lenticels (2.5Y 8/2)    (FIG. 3). Lenticels are round to oval in shape, 1-10 mm×1-3 mm in    size. ‘Ivanhoe’ has a vigor similar to ‘Chandler’.-   Foliage: The dark green foliage is illustrated in FIG. 4 and FIG. 5    and is typical of Juglans regia. Leafing out date between 1999 and    2008 has occurred on March 19^(th) on the average. For comparative    purposes the ‘Chandler’ cultivar leaf-out is April 3^(rd). The    typical leaf coloration is green (adaxial 5GY 4/4, abaxial 5GY 8/2)    The leaves are pinnately compound with 7-9 leaflets. The full leaf    length is approximately 40 cm and width is 29 cm. Leaflets are    broadly elliptical and entire. The terminal leaflet averages 16 cm    in length and 8 cm in width. The middle leaflets average 15 cm in    length and 6 cm in width and the proximal leaflets average 6 cm in    length and 3 cm in width. The rachis averages 23 cm in length and    2-4 mm in diameter. Petiole length is 8 cm and is 5GY 7/8 in color.-   Inflorescence: The tree is precocious with excellent yield being    noted at age 3 years. Male flowers (catkins) were not present until    age 5 years. This delay in male maturity is typical of Juglans    regia. From 1999 to 2008, average first female bloom occurred on    March 23, peak bloom on March 28, and last bloom on April 3. From    2001 to 2008, average male flowering (pollen shedding) began April    1, peaked on April 8, and terminated April 15. In this protogynous    tree, pollen shedding does not completely cover pistillate bloom    suggesting that a pollenizer would be needed for maximum yield in    isolated areas. ‘Sexton’ (U.S. Plant Pat. No. 16,496P3), ‘Payne’    (unpatented), and ‘Serr’ (unpatented) would be satisfactory    pollenizers. The female flowers are typical of Juglans regia    (FIG. 6) with 2-3 flowers per inflorescence borne on 1 cm spike at    both terminal and lateral positions on current season's growth.    Approximately 100% of the lateral buds contain inflorescences making    yields much greater than trees that only bear flowers terminally. A    typical female flower is approximately 5 to 7 mm at anthesis and    floral organs are typical of Juglans regia. The flowers appear    vase-shaped when the 2 plumose stigmatic arms are curved outward.    There are no petals. The female flowers are green (5GY 7/8) in    color. The flower fragrance is typical of Juglans regia and is not    noticeably different than the foliage fragrance. The male flowers    (FIG. 7) are borne on catkins, between 7 and 13 cm in length and 1.5    cm in diameter, and are green in color (5GY 7/8).-   Walnuts: The new cultivar commonly harvests about 4 weeks before    ‘Chandler’ and about 3 days before ‘Payne’. The new cultivar has    excellent yields of mostly large-sized walnuts. The hull is globose,    4.8 cm×4.5 cm, 3 mm thick and 5GY 6/4 in color with numerous lighter    speckles (FIG. 8). The nut is broadly elliptical, very smooth, tan    (7.5YR 8/2) and measures approximately 40 mm in length and 35 mm in    width (FIG. 9). The shell is 1.5 mm thick, relatively strong and    well sealed and the kernel is easy to remove. The kernel weight    averages 7.7 g and makes up 57% of the total nut weight of 13.5 g.    Kernel color is considered excellent and scores mostly in the light    to extra light categories of the USDA Standards for Grades of    Shelled Walnuts as determined by using the standard Walnut Color    Chart for kernels published by the Dried Fruit Association of    California. In addition kernels of ‘Ivanhoe’ scored 53 on the    Relative Light Index used by Diamond Foods of Stockton, Calif. It is    typical of commercial walnuts in terms of flavor and firmness, the    latter varying according to the percent moisture after drying.-   Disease susceptibility: Blight caused by Xanthomonas campestris pv.    juglandis can be a problem on this early leafing cultivar. It may    also be susceptible to sunburn if the nuts are in exposed locations.    Pistillate flower abscission has not been a problem.-   Usage: This new cultivar of the present invention provides an early    season walnut with high quality light-colored kernels that can be    used cracked or in-shell.

TABLE 1 Performance of ‘Ivanhoe’ compared to its parents and ‘Chandler’Variety Trait¹ Ivanhoe² UC67-13³ Chico⁴ Chandler⁵ Leafing date 19 Mar.23 Mar. 22 Mar. 3 Apr. Pollen shed date First 1 Apr. 30 Mar. 6 Apr. 4Apr. Peak 8 Apr. 6 Apr. 12 Apr. 11 Apr. Last 15 Apr. 19 Apr. 20 Apr. 20Apr. Female bloom date First 23 Mar. 6-Apr. 25 Mar. 15 Apr. Peak 28 Mar.11 Apr. 31 Mar. 22 Apr. Last 3 Apr. 19 Apr. 9 Apr. 29 Apr. Harvest date13 Sep. 19 Sep. 17 Sep. 7 Oct. Catkin abundance 5 6 5 5 Female abundance7 6 6 6 Flowers/inflorescence 2 2 2 2 Percent lateral bud fruitfulness100 96 100 95 Yield 7 6 6 6 Shell Texture 4 5 4 5 Color 4 5 5 4 Seal 4 55 5 Strength 5 5 6 4 Integrity 7 7 7 7 Thickness 1.5 1.5 1.5 1.3 Packingtissue 5 5 6 5 Kernel Inshell weight 13.5 15.2 11.4 13.5 Kernel weight7.7 8.4 5.3 6.7 Percent kernel 57 56 47 50 Fill 5 5 6 5 Plumpness 5 5 54 Ease of removal 4 4 6 4 Percent blank 1 2 2 2 Percent extra light 3821 9 49 Percent light 51 73 76 45 Percent light amber 10 4 12 5 Percentamber 1 2 3 0 Percent tip shrivel 1 0 0 28 Percent veins 10 45 19 18 KEYFOR TABLE 1 Tree evaluation Catkin abundance Male flower abundance: 3low; 5 intermediate; 7 high Female abundance Female flower abundance: 3low; 5 intermediate; 7 high Lateral fruitfulness % Percent of lateralbuds with female flowers Yield Yield: 3 low; 5 intermediate; 7 high Nutand kernel traits Texture Shell texture: 3 smooth; 5 medium; 7 roughColor Shell color: 3 light; 5 medium; 7 dark Seal Shell seal: 3 weak; 5intermediate; 7 strong Strength Shell strength: 3 weak; 5 intermediate;7 strong Integrity Shell integrity: 3 substantial area of shell missing;5 small area of missing shell; 6 stem end hole; 7 complete shellThickness Shell thickness at mid-cheek in mm Packing tissue Innerlining: 3 thin; 5 medium; 7 thick Inshell weight g Kernel weight gKernel % Kernel wt/inshell wt × 100 Fill Kernel fill: 3 poor; 5moderate; 7 well Plumpness Kernel plumpness: 3 thin; 5 moderate; 7 plumpEase of removal Ease of removal of kernel halves: 3 easy; 5 moderate; 7difficult Blanks % Percent of nuts without a kernel Extra light %Percent of kernels in extra light category (DFA) Light % Percent ofkernels in light category (DFA) Light amber % Percent of kernels inlight amber category (DFA) Amber % Percent of kernels in amber category(DFA) Tip shrivel % Percent of kernels with tip shrivel like ChandlerVeins % Percent of kernels with conspicuous veins ¹See attached 2 fordescription of scores ²Data 2000-2008 ³Data 1988-2002 ⁴Data 1988-2003⁵Data 1988-2008 DFA Dried Fruit Association of CA

1. A new and distinct variety of walnut tree designated ‘Ivanhoe’ asshown and described herein.